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Chronological xistorv of Revegeta[ion. Areas revegetated prior to 1991 at the Seneca 11 <br />Mine are listed by field number in Table 6 and shown on Exhibit 90.3, Chronological History <br />of Revegetation Activities of [he 1990 Annual Reclamation Report (PCC, 1991). Areas <br />revegetated in 1991 and years following are reported in the appropriate annual reports. <br />Sedimentation Pond Surveys <br />Peabody is required by Permit C-80-005 to monitor sedimentation ponds for sediment storage <br />capacities. In TR-15, CM LRD approved the following frequency schedule to conduct sediment <br />surveys for the ponds at Seneca II Mine. <br />Sedimentation Pond_______ _______ Fre~c uency_ _________ ________N ext Scheduled Survey <br />002 Once Every 5 Years 1998• <br />003 Once Every 5 Years 1998• <br />004 Once Every 2 Years 1995• <br />008 Once Every 2 Years 1995• <br />• • PMCC recommends the next survey be completed in 1996. <br />This schedule provides a sediment yield history and allow advance warning to operations <br />personnel when sediment clean-out work is required. In accordance with Rule 4.05 .6(11)(c), ' <br />Peabody visually inspects each pond a minimum of quarterly each year. During these <br />inspections, any drastic change in sedimentation storage or sudden increase in a sediment <br />delta at the inlet to the pond could be detected which would require mitigative action. <br />No sediment clean-out uo rk was conducted during 1993 for the sedimentation ponds at Seneca ~, <br />II Mine. Sediment Ponds 002, 003, 004, and 008 were surveyed in July 1993 for sediment ~~ <br />determination. As stated in the past, ponds containing water are very difficult to survey <br />and obtain a high degree of accuracy. In 1993, Seneca adopted a new approach to sediment <br />surveys. That is, concentrating the survey shots in an area where the most sediment <br />deposition is likely to occur. <br />Based on the 1993 survey, all sediment ponds have sufficient sediment storage. <br />additionally, all ponds have been discharging in compliance with the approved NPDES permit <br />effluent limitations. Yearly sediment delivery estimates to the ponds is considerably less <br />than originally calculated. <br />• <br />13 <br />